SU885753A1 - Solution drying method - Google Patents

Description

(54) METHOD FOR DRYING SOLUTIONS

I

The invention relates to a drying technique and can be used in the medical, chemical, food and other industries for drying, advantageously heat-sensitive and sticky materials.

A known installation for drying solutions 8 of which is implemented a method of drying them by dispersing the material to be dried in a fluidized bed of inert bodies with simultaneous flow under the latter of central and peripheral coolant flows, the first of which is formed by a series of parallel annular jets 1.

The disadvantages of this method are with a decrease in the intensity and stability of the process during the drying of sticky materials, as well as high energy consumption.

The purpose of the invention is to intensify the drying process and reduce energy costs.

This goal is achieved by the fact that the central flow of heat-transfer fluid is supplied with a temperature of 150-180 ° C with the direction of its part to the spray area of the material being dried, and the peripheral flow rate is supplied with a temperature of 80-120 ° C. and dale

the latter is 60-70% of the total amount of coolant.

The drawing shows schematically an installation for carrying out the proposed method.

The installation contains a drying chamber I of a cylindrical shape, in the lower part of which there is a gas distributor grate 2 with nozzle 3 and inertial bodies 4. Air nozzles 5 are installed above the layer of inert bodies 4, inside which 10 nozzles 6 are coaxially mounted and directed to the top of nozzle 3. Before the drying chamber 1 houses a heater 7. A duct 8 is attached to the calorifer 7, which is connected to the nozzle 3. and air nozzles 5. In the duct 8 is installed an additional heater 9. At the outlet of the drying chamber 1 a cyclone 10 s is installed discharge hopper 11.

Before feeding into the drying chamber 1, the entire coolant is heated in the heater 7 to a temperature of 80-120 ° C. Then, the zeolite heat carrier flux is heated in the heater 9 to a temperature of 150-180 ° C and fed through the duct 8 to the nozzle 3. The peripheral heat carrier flow evenly distributed over the cross section of the chamber 1 by means of the gas distribution grid 2, fluidizing the support bodies 4. 3, the central flow of the coolant is supplied in the direction from the center to the periphery in the form of a series of parallel annular jets. Due to this, reliable circulation of inert bodies 4 along the following contour is maintained: upward movement in the center of chamber I (above nozzle 3) - downward movement along the walls of chamber 1.

In addition, along the branch duct 8, the heat carrier heated in the heater 9 enters the air nozzles 5, which are evenly spaced around the perimeter of the chamber in the upper boundary of the fluidized bed of inert bodies 4, and covers the plumes of the dispersible solution entering through the nozzles 6. This is an intensive preliminary drying the solution in the flares of the nozzles 5. The pre-dried material goes further into the high-temperature zone of the upward movement of the inert bodies 4 above the nozzle 3. In this zone due to the meeting The flow of the dried product (from above) and the heated central flow of heat-transfer fluid in the form of a series of parallel annular jets with hot inert bodies 4 (below) results in intensive drying of the material. The final drying and its collapse in the form of dust occurs in the regime of intensive fluidization by a peripheral flow of heat carrier with

temperature 80-120 ° C. The spent coolant with pulverized dry material enters the cyclone 10, and the material collected in bunker II is taken for packaging.

The choice of the temperature range of the coolant is determined by the properties of the material being dried (calcium pantothenate). With prolonged exposure to temperatures above 120 ° C, the material begins to decompose. This determines the upper limit of the temperature. At temperatures below 80 ° C, it is not economically feasible to conduct the process, since the intensity of drying drops sharply.

Despite the fact that the temperature of the central flow of the coolant and flows covering the plumes of the dispatched magnetic spring. can reach loOC, decomposition of the material does not occur, as it is in the high temperature zone of a fraction of a second. However, this time is quite enough for the inert bodies of 4 mothers to get already dried, which prevents sticking of the layers. The decrease in energy consumption is due to the fact that with high nitiness of the drying process only 30–40% of the heat carrier is heated to a temperature of 150–180 ° C. The remaining 70-60 ° / o heated to 120-80 ° C.

Glass beads with a diameter of 2.5-3 mm are used as inner bodies 4. The weight of a single load is 200 kg with a chamber of 0.8 m. The flow rate of the peripheral flow is 5500-6000 kg / h, and the flow rate of the central one is 1000-1200 kg / h. Example I. Temperature of the heat transfer medium heat exchanger 85 ° С, temperature of the central heat flow flow agent 150 ° С, leaving air temperature.

In this case, the plant capacity is 45 kg / h in terms of evaporated moisture.

Example 2. The temperature of the periphery of the flow of thermals is 100 ° C, the temperature of the central flow of the heat carrier is 160 ° C, the temperature of the leaving air is 80 ° C.

In this case, the capacity is about kg / hr on evaporating moisture. Example 3. The temperature of the peripheral flow of the IMC heat carrier, the temperature of the central flow of the coolant is 180 C, the temperature of the leaving air is 85 ° C.

In this case, the capacity is 70 kg / h in terms of evaporated moisture.

Claims (1)

Invention Formula The method of drying solutions, which are superior to calcium calcium, by dispersing it, spraying the dried material in a fluidized bed of inert bodies from the central and peripheral coolant flow, the first of which is formed by a number of parallel annular jets, characterized in that, in order to intensify the drying process and reduction of energy consumption, the central flow of the heat-dissipation fluid is supplied with a temperature of 150-180 ° C with the direction of its part in the spray area of the material being dried, and the peripheral flow is fed with temperature, and The proportion of the latter is 50-70% of the total amount of heat carrier. Sources of information taken into account during the examination 1. USSR Copyright Certificate № 580426, cl. F26 B 17/10, 1975.